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<a class="jxr_linenumber" name="1" href="#1">1</a>   <em class="jxr_comment">/*</em>
<a class="jxr_linenumber" name="2" href="#2">2</a>   <em class="jxr_comment"> * Copyright 2012 The Netty Project</em>
<a class="jxr_linenumber" name="3" href="#3">3</a>   <em class="jxr_comment"> *</em>
<a class="jxr_linenumber" name="4" href="#4">4</a>   <em class="jxr_comment"> * The Netty Project licenses this file to you under the Apache License,</em>
<a class="jxr_linenumber" name="5" href="#5">5</a>   <em class="jxr_comment"> * version 2.0 (the "License"); you may not use this file except in compliance</em>
<a class="jxr_linenumber" name="6" href="#6">6</a>   <em class="jxr_comment"> * with the License. You may obtain a copy of the License at:</em>
<a class="jxr_linenumber" name="7" href="#7">7</a>   <em class="jxr_comment"> *</em>
<a class="jxr_linenumber" name="8" href="#8">8</a>   <em class="jxr_comment"> *   <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a class="jxr_linenumber" name="9" href="#9">9</a>   <em class="jxr_comment"> *</em>
<a class="jxr_linenumber" name="10" href="#10">10</a>  <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing, software</em>
<a class="jxr_linenumber" name="11" href="#11">11</a>  <em class="jxr_comment"> * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT</em>
<a class="jxr_linenumber" name="12" href="#12">12</a>  <em class="jxr_comment"> * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the</em>
<a class="jxr_linenumber" name="13" href="#13">13</a>  <em class="jxr_comment"> * License for the specific language governing permissions and limitations</em>
<a class="jxr_linenumber" name="14" href="#14">14</a>  <em class="jxr_comment"> * under the License.</em>
<a class="jxr_linenumber" name="15" href="#15">15</a>  <em class="jxr_comment"> */</em>
<a class="jxr_linenumber" name="16" href="#16">16</a>  <strong class="jxr_keyword">package</strong> org.jboss.netty.handler.codec.frame;
<a class="jxr_linenumber" name="17" href="#17">17</a>  
<a class="jxr_linenumber" name="18" href="#18">18</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.buffer.ChannelBuffer;
<a class="jxr_linenumber" name="19" href="#19">19</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.buffer.ChannelBufferFactory;
<a class="jxr_linenumber" name="20" href="#20">20</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.buffer.ChannelBuffers;
<a class="jxr_linenumber" name="21" href="#21">21</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.buffer.CompositeChannelBuffer;
<a class="jxr_linenumber" name="22" href="#22">22</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.Channel;
<a class="jxr_linenumber" name="23" href="#23">23</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.ChannelHandler;
<a class="jxr_linenumber" name="24" href="#24">24</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.ChannelHandlerContext;
<a class="jxr_linenumber" name="25" href="#25">25</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.ChannelPipeline;
<a class="jxr_linenumber" name="26" href="#26">26</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.ChannelStateEvent;
<a class="jxr_linenumber" name="27" href="#27">27</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.ChannelUpstreamHandler;
<a class="jxr_linenumber" name="28" href="#28">28</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.Channels;
<a class="jxr_linenumber" name="29" href="#29">29</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.ExceptionEvent;
<a class="jxr_linenumber" name="30" href="#30">30</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.LifeCycleAwareChannelHandler;
<a class="jxr_linenumber" name="31" href="#31">31</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.MessageEvent;
<a class="jxr_linenumber" name="32" href="#32">32</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.channel.SimpleChannelUpstreamHandler;
<a class="jxr_linenumber" name="33" href="#33">33</a>  <strong class="jxr_keyword">import</strong> org.jboss.netty.handler.codec.replay.ReplayingDecoder;
<a class="jxr_linenumber" name="34" href="#34">34</a>  
<a class="jxr_linenumber" name="35" href="#35">35</a>  <strong class="jxr_keyword">import</strong> java.net.SocketAddress;
<a class="jxr_linenumber" name="36" href="#36">36</a>  
<a class="jxr_linenumber" name="37" href="#37">37</a>  <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="38" href="#38">38</a>  <em class="jxr_javadoccomment"> * Decodes the received {@link ChannelBuffer}s into a meaningful frame object.</em>
<a class="jxr_linenumber" name="39" href="#39">39</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="40" href="#40">40</a>  <em class="jxr_javadoccomment"> * In a stream-based transport such as TCP/IP, packets can be fragmented and</em>
<a class="jxr_linenumber" name="41" href="#41">41</a>  <em class="jxr_javadoccomment"> * reassembled during transmission even in a LAN environment.  For example,</em>
<a class="jxr_linenumber" name="42" href="#42">42</a>  <em class="jxr_javadoccomment"> * let us assume you have received three packets:</em>
<a class="jxr_linenumber" name="43" href="#43">43</a>  <em class="jxr_javadoccomment"> * &lt;pre&gt;</em>
<a class="jxr_linenumber" name="44" href="#44">44</a>  <em class="jxr_javadoccomment"> * +-----+-----+-----+</em>
<a class="jxr_linenumber" name="45" href="#45">45</a>  <em class="jxr_javadoccomment"> * | ABC | DEF | GHI |</em>
<a class="jxr_linenumber" name="46" href="#46">46</a>  <em class="jxr_javadoccomment"> * +-----+-----+-----+</em>
<a class="jxr_linenumber" name="47" href="#47">47</a>  <em class="jxr_javadoccomment"> * &lt;/pre&gt;</em>
<a class="jxr_linenumber" name="48" href="#48">48</a>  <em class="jxr_javadoccomment"> * because of the packet fragmentation, a server can receive them like the</em>
<a class="jxr_linenumber" name="49" href="#49">49</a>  <em class="jxr_javadoccomment"> * following:</em>
<a class="jxr_linenumber" name="50" href="#50">50</a>  <em class="jxr_javadoccomment"> * &lt;pre&gt;</em>
<a class="jxr_linenumber" name="51" href="#51">51</a>  <em class="jxr_javadoccomment"> * +----+-------+---+---+</em>
<a class="jxr_linenumber" name="52" href="#52">52</a>  <em class="jxr_javadoccomment"> * | AB | CDEFG | H | I |</em>
<a class="jxr_linenumber" name="53" href="#53">53</a>  <em class="jxr_javadoccomment"> * +----+-------+---+---+</em>
<a class="jxr_linenumber" name="54" href="#54">54</a>  <em class="jxr_javadoccomment"> * &lt;/pre&gt;</em>
<a class="jxr_linenumber" name="55" href="#55">55</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="56" href="#56">56</a>  <em class="jxr_javadoccomment"> * {@link FrameDecoder} helps you defrag the received packets into one or more</em>
<a class="jxr_linenumber" name="57" href="#57">57</a>  <em class="jxr_javadoccomment"> * meaningful &lt;strong&gt;frames&lt;/strong&gt; that could be easily understood by the</em>
<a class="jxr_linenumber" name="58" href="#58">58</a>  <em class="jxr_javadoccomment"> * application logic.  In case of the example above, your {@link FrameDecoder}</em>
<a class="jxr_linenumber" name="59" href="#59">59</a>  <em class="jxr_javadoccomment"> * implementation could defrag the received packets like the following:</em>
<a class="jxr_linenumber" name="60" href="#60">60</a>  <em class="jxr_javadoccomment"> * &lt;pre&gt;</em>
<a class="jxr_linenumber" name="61" href="#61">61</a>  <em class="jxr_javadoccomment"> * +-----+-----+-----+</em>
<a class="jxr_linenumber" name="62" href="#62">62</a>  <em class="jxr_javadoccomment"> * | ABC | DEF | GHI |</em>
<a class="jxr_linenumber" name="63" href="#63">63</a>  <em class="jxr_javadoccomment"> * +-----+-----+-----+</em>
<a class="jxr_linenumber" name="64" href="#64">64</a>  <em class="jxr_javadoccomment"> * &lt;/pre&gt;</em>
<a class="jxr_linenumber" name="65" href="#65">65</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="66" href="#66">66</a>  <em class="jxr_javadoccomment"> * The following code shows an example handler which decodes a frame whose</em>
<a class="jxr_linenumber" name="67" href="#67">67</a>  <em class="jxr_javadoccomment"> * first 4 bytes header represents the length of the frame, excluding the</em>
<a class="jxr_linenumber" name="68" href="#68">68</a>  <em class="jxr_javadoccomment"> * header.</em>
<a class="jxr_linenumber" name="69" href="#69">69</a>  <em class="jxr_javadoccomment"> * &lt;pre&gt;</em>
<a class="jxr_linenumber" name="70" href="#70">70</a>  <em class="jxr_javadoccomment"> * MESSAGE FORMAT</em>
<a class="jxr_linenumber" name="71" href="#71">71</a>  <em class="jxr_javadoccomment"> * ==============</em>
<a class="jxr_linenumber" name="72" href="#72">72</a>  <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="73" href="#73">73</a>  <em class="jxr_javadoccomment"> * Offset:  0        4                   (Length + 4)</em>
<a class="jxr_linenumber" name="74" href="#74">74</a>  <em class="jxr_javadoccomment"> *          +--------+------------------------+</em>
<a class="jxr_linenumber" name="75" href="#75">75</a>  <em class="jxr_javadoccomment"> * Fields:  | Length | Actual message content |</em>
<a class="jxr_linenumber" name="76" href="#76">76</a>  <em class="jxr_javadoccomment"> *          +--------+------------------------+</em>
<a class="jxr_linenumber" name="77" href="#77">77</a>  <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="78" href="#78">78</a>  <em class="jxr_javadoccomment"> * DECODER IMPLEMENTATION</em>
<a class="jxr_linenumber" name="79" href="#79">79</a>  <em class="jxr_javadoccomment"> * ======================</em>
<a class="jxr_linenumber" name="80" href="#80">80</a>  <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="81" href="#81">81</a>  <em class="jxr_javadoccomment"> * public class IntegerHeaderFrameDecoder extends {@link FrameDecoder} {</em>
<a class="jxr_linenumber" name="82" href="#82">82</a>  <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="83" href="#83">83</a>  <em class="jxr_javadoccomment"> *   {@code @Override}</em>
<a class="jxr_linenumber" name="84" href="#84">84</a>  <em class="jxr_javadoccomment"> *   protected Object decode({@link ChannelHandlerContext} ctx,</em>
<a class="jxr_linenumber" name="85" href="#85">85</a>  <em class="jxr_javadoccomment"> *                           {@link Channel channel},</em>
<a class="jxr_linenumber" name="86" href="#86">86</a>  <em class="jxr_javadoccomment"> *                           {@link ChannelBuffer} buf) throws Exception {</em>
<a class="jxr_linenumber" name="87" href="#87">87</a>  <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="88" href="#88">88</a>  <em class="jxr_javadoccomment"> *     // Make sure if the length field was received.</em>
<a class="jxr_linenumber" name="89" href="#89">89</a>  <em class="jxr_javadoccomment"> *     if (buf.readableBytes() &amp;lt; 4) {</em>
<a class="jxr_linenumber" name="90" href="#90">90</a>  <em class="jxr_javadoccomment"> *        // The length field was not received yet - return null.</em>
<a class="jxr_linenumber" name="91" href="#91">91</a>  <em class="jxr_javadoccomment"> *        // This method will be invoked again when more packets are</em>
<a class="jxr_linenumber" name="92" href="#92">92</a>  <em class="jxr_javadoccomment"> *        // received and appended to the buffer.</em>
<a class="jxr_linenumber" name="93" href="#93">93</a>  <em class="jxr_javadoccomment"> *        return &lt;strong&gt;null&lt;/strong&gt;;</em>
<a class="jxr_linenumber" name="94" href="#94">94</a>  <em class="jxr_javadoccomment"> *     }</em>
<a class="jxr_linenumber" name="95" href="#95">95</a>  <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="96" href="#96">96</a>  <em class="jxr_javadoccomment"> *     // The length field is in the buffer.</em>
<a class="jxr_linenumber" name="97" href="#97">97</a>  <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="98" href="#98">98</a>  <em class="jxr_javadoccomment"> *     // Mark the current buffer position before reading the length field</em>
<a class="jxr_linenumber" name="99" href="#99">99</a>  <em class="jxr_javadoccomment"> *     // because the whole frame might not be in the buffer yet.</em>
<a class="jxr_linenumber" name="100" href="#100">100</a> <em class="jxr_javadoccomment"> *     // We will reset the buffer position to the marked position if</em>
<a class="jxr_linenumber" name="101" href="#101">101</a> <em class="jxr_javadoccomment"> *     // there's not enough bytes in the buffer.</em>
<a class="jxr_linenumber" name="102" href="#102">102</a> <em class="jxr_javadoccomment"> *     buf.markReaderIndex();</em>
<a class="jxr_linenumber" name="103" href="#103">103</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="104" href="#104">104</a> <em class="jxr_javadoccomment"> *     // Read the length field.</em>
<a class="jxr_linenumber" name="105" href="#105">105</a> <em class="jxr_javadoccomment"> *     int length = buf.readInt();</em>
<a class="jxr_linenumber" name="106" href="#106">106</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="107" href="#107">107</a> <em class="jxr_javadoccomment"> *     // Make sure if there's enough bytes in the buffer.</em>
<a class="jxr_linenumber" name="108" href="#108">108</a> <em class="jxr_javadoccomment"> *     if (buf.readableBytes() &amp;lt; length) {</em>
<a class="jxr_linenumber" name="109" href="#109">109</a> <em class="jxr_javadoccomment"> *        // The whole bytes were not received yet - return null.</em>
<a class="jxr_linenumber" name="110" href="#110">110</a> <em class="jxr_javadoccomment"> *        // This method will be invoked again when more packets are</em>
<a class="jxr_linenumber" name="111" href="#111">111</a> <em class="jxr_javadoccomment"> *        // received and appended to the buffer.</em>
<a class="jxr_linenumber" name="112" href="#112">112</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="113" href="#113">113</a> <em class="jxr_javadoccomment"> *        // Reset to the marked position to read the length field again</em>
<a class="jxr_linenumber" name="114" href="#114">114</a> <em class="jxr_javadoccomment"> *        // next time.</em>
<a class="jxr_linenumber" name="115" href="#115">115</a> <em class="jxr_javadoccomment"> *        buf.resetReaderIndex();</em>
<a class="jxr_linenumber" name="116" href="#116">116</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="117" href="#117">117</a> <em class="jxr_javadoccomment"> *        return &lt;strong&gt;null&lt;/strong&gt;;</em>
<a class="jxr_linenumber" name="118" href="#118">118</a> <em class="jxr_javadoccomment"> *     }</em>
<a class="jxr_linenumber" name="119" href="#119">119</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="120" href="#120">120</a> <em class="jxr_javadoccomment"> *     // There's enough bytes in the buffer. Read it.</em>
<a class="jxr_linenumber" name="121" href="#121">121</a> <em class="jxr_javadoccomment"> *     {@link ChannelBuffer} frame = buf.readBytes(length);</em>
<a class="jxr_linenumber" name="122" href="#122">122</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="123" href="#123">123</a> <em class="jxr_javadoccomment"> *     // Successfully decoded a frame.  Return the decoded frame.</em>
<a class="jxr_linenumber" name="124" href="#124">124</a> <em class="jxr_javadoccomment"> *     return &lt;strong&gt;frame&lt;/strong&gt;;</em>
<a class="jxr_linenumber" name="125" href="#125">125</a> <em class="jxr_javadoccomment"> *   }</em>
<a class="jxr_linenumber" name="126" href="#126">126</a> <em class="jxr_javadoccomment"> * }</em>
<a class="jxr_linenumber" name="127" href="#127">127</a> <em class="jxr_javadoccomment"> * &lt;/pre&gt;</em>
<a class="jxr_linenumber" name="128" href="#128">128</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="129" href="#129">129</a> <em class="jxr_javadoccomment"> * &lt;h3&gt;Returning a POJO rather than a {@link ChannelBuffer}&lt;/h3&gt;</em>
<a class="jxr_linenumber" name="130" href="#130">130</a> <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="131" href="#131">131</a> <em class="jxr_javadoccomment"> * Please note that you can return an object of a different type than</em>
<a class="jxr_linenumber" name="132" href="#132">132</a> <em class="jxr_javadoccomment"> * {@link ChannelBuffer} in your {@code decode()} and {@code decodeLast()}</em>
<a class="jxr_linenumber" name="133" href="#133">133</a> <em class="jxr_javadoccomment"> * implementation.  For example, you could return a</em>
<a class="jxr_linenumber" name="134" href="#134">134</a> <em class="jxr_javadoccomment"> * &lt;a href="<a href="http://en.wikipedia.org/wiki/POJO" target="alexandria_uri">http://en.wikipedia.org/wiki/POJO</a>"&gt;POJO&lt;/a&gt; so that the next</em>
<a class="jxr_linenumber" name="135" href="#135">135</a> <em class="jxr_javadoccomment"> * {@link ChannelUpstreamHandler} receives a {@link MessageEvent} which</em>
<a class="jxr_linenumber" name="136" href="#136">136</a> <em class="jxr_javadoccomment"> * contains a POJO rather than a {@link ChannelBuffer}.</em>
<a class="jxr_linenumber" name="137" href="#137">137</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="138" href="#138">138</a> <em class="jxr_javadoccomment"> * &lt;h3&gt;Replacing a decoder with another decoder in a pipeline&lt;/h3&gt;</em>
<a class="jxr_linenumber" name="139" href="#139">139</a> <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="140" href="#140">140</a> <em class="jxr_javadoccomment"> * If you are going to write a protocol multiplexer, you will probably want to</em>
<a class="jxr_linenumber" name="141" href="#141">141</a> <em class="jxr_javadoccomment"> * replace a {@link FrameDecoder} (protocol detector) with another</em>
<a class="jxr_linenumber" name="142" href="#142">142</a> <em class="jxr_javadoccomment"> * {@link FrameDecoder} or {@link ReplayingDecoder} (actual protocol decoder).</em>
<a class="jxr_linenumber" name="143" href="#143">143</a> <em class="jxr_javadoccomment"> * It is not possible to achieve this simply by calling</em>
<a class="jxr_linenumber" name="144" href="#144">144</a> <em class="jxr_javadoccomment"> * {@link ChannelPipeline#replace(ChannelHandler, String, ChannelHandler)}, but</em>
<a class="jxr_linenumber" name="145" href="#145">145</a> <em class="jxr_javadoccomment"> * some additional steps are required:</em>
<a class="jxr_linenumber" name="146" href="#146">146</a> <em class="jxr_javadoccomment"> * &lt;pre&gt;</em>
<a class="jxr_linenumber" name="147" href="#147">147</a> <em class="jxr_javadoccomment"> * public class FirstDecoder extends {@link FrameDecoder} {</em>
<a class="jxr_linenumber" name="148" href="#148">148</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="149" href="#149">149</a> <em class="jxr_javadoccomment"> *     public FirstDecoder() {</em>
<a class="jxr_linenumber" name="150" href="#150">150</a> <em class="jxr_javadoccomment"> *         super(true); // Enable unfold</em>
<a class="jxr_linenumber" name="151" href="#151">151</a> <em class="jxr_javadoccomment"> *     }</em>
<a class="jxr_linenumber" name="152" href="#152">152</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="153" href="#153">153</a> <em class="jxr_javadoccomment"> *     {@code @Override}</em>
<a class="jxr_linenumber" name="154" href="#154">154</a> <em class="jxr_javadoccomment"> *     protected Object decode({@link ChannelHandlerContext} ctx,</em>
<a class="jxr_linenumber" name="155" href="#155">155</a> <em class="jxr_javadoccomment"> *                             {@link Channel} channel,</em>
<a class="jxr_linenumber" name="156" href="#156">156</a> <em class="jxr_javadoccomment"> *                             {@link ChannelBuffer} buf) {</em>
<a class="jxr_linenumber" name="157" href="#157">157</a> <em class="jxr_javadoccomment"> *         ...</em>
<a class="jxr_linenumber" name="158" href="#158">158</a> <em class="jxr_javadoccomment"> *         // Decode the first message</em>
<a class="jxr_linenumber" name="159" href="#159">159</a> <em class="jxr_javadoccomment"> *         Object firstMessage = ...;</em>
<a class="jxr_linenumber" name="160" href="#160">160</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="161" href="#161">161</a> <em class="jxr_javadoccomment"> *         // Add the second decoder</em>
<a class="jxr_linenumber" name="162" href="#162">162</a> <em class="jxr_javadoccomment"> *         ctx.getPipeline().addLast("second", new SecondDecoder());</em>
<a class="jxr_linenumber" name="163" href="#163">163</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="164" href="#164">164</a> <em class="jxr_javadoccomment"> *         // Remove the first decoder (me)</em>
<a class="jxr_linenumber" name="165" href="#165">165</a> <em class="jxr_javadoccomment"> *         ctx.getPipeline().remove(this);</em>
<a class="jxr_linenumber" name="166" href="#166">166</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="167" href="#167">167</a> <em class="jxr_javadoccomment"> *         if (buf.readable()) {</em>
<a class="jxr_linenumber" name="168" href="#168">168</a> <em class="jxr_javadoccomment"> *             // Hand off the remaining data to the second decoder</em>
<a class="jxr_linenumber" name="169" href="#169">169</a> <em class="jxr_javadoccomment"> *             return new Object[] { firstMessage, buf.readBytes(buf.readableBytes()) };</em>
<a class="jxr_linenumber" name="170" href="#170">170</a> <em class="jxr_javadoccomment"> *         } else {</em>
<a class="jxr_linenumber" name="171" href="#171">171</a> <em class="jxr_javadoccomment"> *             // Nothing to hand off</em>
<a class="jxr_linenumber" name="172" href="#172">172</a> <em class="jxr_javadoccomment"> *             return firstMessage;</em>
<a class="jxr_linenumber" name="173" href="#173">173</a> <em class="jxr_javadoccomment"> *         }</em>
<a class="jxr_linenumber" name="174" href="#174">174</a> <em class="jxr_javadoccomment"> *     }</em>
<a class="jxr_linenumber" name="175" href="#175">175</a> <em class="jxr_javadoccomment"> * }</em>
<a class="jxr_linenumber" name="176" href="#176">176</a> <em class="jxr_javadoccomment"> * &lt;/pre&gt;</em>
<a class="jxr_linenumber" name="177" href="#177">177</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="178" href="#178">178</a> <em class="jxr_javadoccomment"> * @apiviz.landmark</em>
<a class="jxr_linenumber" name="179" href="#179">179</a> <em class="jxr_javadoccomment"> */</em>
<a class="jxr_linenumber" name="180" href="#180">180</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../../../org/jboss/netty/handler/codec/frame/FrameDecoder.html">FrameDecoder</a> <strong class="jxr_keyword">extends</strong> <a href="../../../../../../org/jboss/netty/channel/SimpleChannelUpstreamHandler.html">SimpleChannelUpstreamHandler</a> <strong class="jxr_keyword">implements</strong> <a href="../../../../../../org/jboss/netty/channel/LifeCycleAwareChannelHandler.html">LifeCycleAwareChannelHandler</a> {
<a class="jxr_linenumber" name="181" href="#181">181</a> 
<a class="jxr_linenumber" name="182" href="#182">182</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS = 1024;
<a class="jxr_linenumber" name="183" href="#183">183</a> 
<a class="jxr_linenumber" name="184" href="#184">184</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">boolean</strong> unfold;
<a class="jxr_linenumber" name="185" href="#185">185</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> cumulation;
<a class="jxr_linenumber" name="186" href="#186">186</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">volatile</strong> <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx;
<a class="jxr_linenumber" name="187" href="#187">187</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">int</strong> copyThreshold;
<a class="jxr_linenumber" name="188" href="#188">188</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">int</strong> maxCumulationBufferComponents = DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS;
<a class="jxr_linenumber" name="189" href="#189">189</a> 
<a class="jxr_linenumber" name="190" href="#190">190</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/handler/codec/frame/FrameDecoder.html">FrameDecoder</a>() {
<a class="jxr_linenumber" name="191" href="#191">191</a>         <strong class="jxr_keyword">this</strong>(false);
<a class="jxr_linenumber" name="192" href="#192">192</a>     }
<a class="jxr_linenumber" name="193" href="#193">193</a> 
<a class="jxr_linenumber" name="194" href="#194">194</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/handler/codec/frame/FrameDecoder.html">FrameDecoder</a>(<strong class="jxr_keyword">boolean</strong> unfold) {
<a class="jxr_linenumber" name="195" href="#195">195</a>         <strong class="jxr_keyword">this</strong>.unfold = unfold;
<a class="jxr_linenumber" name="196" href="#196">196</a>     }
<a class="jxr_linenumber" name="197" href="#197">197</a> 
<a class="jxr_linenumber" name="198" href="#198">198</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">boolean</strong> isUnfold() {
<a class="jxr_linenumber" name="199" href="#199">199</a>         <strong class="jxr_keyword">return</strong> unfold;
<a class="jxr_linenumber" name="200" href="#200">200</a>     }
<a class="jxr_linenumber" name="201" href="#201">201</a> 
<a class="jxr_linenumber" name="202" href="#202">202</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">void</strong> setUnfold(<strong class="jxr_keyword">boolean</strong> unfold) {
<a class="jxr_linenumber" name="203" href="#203">203</a>         <strong class="jxr_keyword">if</strong> (ctx == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="204" href="#204">204</a>             <strong class="jxr_keyword">this</strong>.unfold = unfold;
<a class="jxr_linenumber" name="205" href="#205">205</a>         } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="206" href="#206">206</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalStateException(
<a class="jxr_linenumber" name="207" href="#207">207</a>                     <span class="jxr_string">"decoder properties cannot be changed once the decoder is added to a pipeline."</span>);
<a class="jxr_linenumber" name="208" href="#208">208</a>         }
<a class="jxr_linenumber" name="209" href="#209">209</a>     }
<a class="jxr_linenumber" name="210" href="#210">210</a> 
<a class="jxr_linenumber" name="211" href="#211">211</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="212" href="#212">212</a> <em class="jxr_javadoccomment">     * See {@link #setMaxCumulationBufferCapacity(int)} for explaintation of this setting</em>
<a class="jxr_linenumber" name="213" href="#213">213</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="214" href="#214">214</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="215" href="#215">215</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> getMaxCumulationBufferCapacity() {
<a class="jxr_linenumber" name="216" href="#216">216</a>         <strong class="jxr_keyword">return</strong> copyThreshold;
<a class="jxr_linenumber" name="217" href="#217">217</a>     }
<a class="jxr_linenumber" name="218" href="#218">218</a> 
<a class="jxr_linenumber" name="219" href="#219">219</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="220" href="#220">220</a> <em class="jxr_javadoccomment">     * Set the maximal capacity of the internal cumulation ChannelBuffer to use</em>
<a class="jxr_linenumber" name="221" href="#221">221</a> <em class="jxr_javadoccomment">     * before the {@link FrameDecoder} tries to minimize the memory usage by</em>
<a class="jxr_linenumber" name="222" href="#222">222</a> <em class="jxr_javadoccomment">     * "byte copy".</em>
<a class="jxr_linenumber" name="223" href="#223">223</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="224" href="#224">224</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="225" href="#225">225</a> <em class="jxr_javadoccomment">     * What you use here really depends on your application and need. Using</em>
<a class="jxr_linenumber" name="226" href="#226">226</a> <em class="jxr_javadoccomment">     * {@link Integer#MAX_VALUE} will disable all byte copies but give you the</em>
<a class="jxr_linenumber" name="227" href="#227">227</a> <em class="jxr_javadoccomment">     * cost of a higher memory usage if big {@link ChannelBuffer}'s will be</em>
<a class="jxr_linenumber" name="228" href="#228">228</a> <em class="jxr_javadoccomment">     * received.</em>
<a class="jxr_linenumber" name="229" href="#229">229</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="230" href="#230">230</a> <em class="jxr_javadoccomment">     * By default a threshold of {@code 0} is used, which means it will</em>
<a class="jxr_linenumber" name="231" href="#231">231</a> <em class="jxr_javadoccomment">     * always copy to try to reduce memory usage</em>
<a class="jxr_linenumber" name="232" href="#232">232</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="233" href="#233">233</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="234" href="#234">234</a> <em class="jxr_javadoccomment">     * @param copyThreshold</em>
<a class="jxr_linenumber" name="235" href="#235">235</a> <em class="jxr_javadoccomment">     *            the threshold (in bytes) or {@link Integer#MAX_VALUE} to</em>
<a class="jxr_linenumber" name="236" href="#236">236</a> <em class="jxr_javadoccomment">     *            disable it. The value must be at least 0</em>
<a class="jxr_linenumber" name="237" href="#237">237</a> <em class="jxr_javadoccomment">     * @throws IllegalStateException</em>
<a class="jxr_linenumber" name="238" href="#238">238</a> <em class="jxr_javadoccomment">     *             get thrown if someone tries to change this setting after the</em>
<a class="jxr_linenumber" name="239" href="#239">239</a> <em class="jxr_javadoccomment">     *             Decoder was added to the {@link ChannelPipeline}</em>
<a class="jxr_linenumber" name="240" href="#240">240</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="241" href="#241">241</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">void</strong> setMaxCumulationBufferCapacity(<strong class="jxr_keyword">int</strong> copyThreshold) {
<a class="jxr_linenumber" name="242" href="#242">242</a>         <strong class="jxr_keyword">if</strong> (copyThreshold &lt; 0) {
<a class="jxr_linenumber" name="243" href="#243">243</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalArgumentException(<span class="jxr_string">"maxCumulationBufferCapacity must be &gt;= 0"</span>);
<a class="jxr_linenumber" name="244" href="#244">244</a>         }
<a class="jxr_linenumber" name="245" href="#245">245</a>         <strong class="jxr_keyword">if</strong> (ctx == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="246" href="#246">246</a>             <strong class="jxr_keyword">this</strong>.copyThreshold = copyThreshold;
<a class="jxr_linenumber" name="247" href="#247">247</a>         } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="248" href="#248">248</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalStateException(
<a class="jxr_linenumber" name="249" href="#249">249</a>                     <span class="jxr_string">"decoder properties cannot be changed once the decoder is added to a pipeline."</span>);
<a class="jxr_linenumber" name="250" href="#250">250</a>         }
<a class="jxr_linenumber" name="251" href="#251">251</a>     }
<a class="jxr_linenumber" name="252" href="#252">252</a> 
<a class="jxr_linenumber" name="253" href="#253">253</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="254" href="#254">254</a> <em class="jxr_javadoccomment">     * Returns the maximum number of components in the cumulation buffer.  If the number of</em>
<a class="jxr_linenumber" name="255" href="#255">255</a> <em class="jxr_javadoccomment">     * the components in the cumulation buffer exceeds this value, the components of the</em>
<a class="jxr_linenumber" name="256" href="#256">256</a> <em class="jxr_javadoccomment">     * cumulation buffer are consolidated into a single component, involving memory copies.</em>
<a class="jxr_linenumber" name="257" href="#257">257</a> <em class="jxr_javadoccomment">     * The default value of this property {@link #DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS}.</em>
<a class="jxr_linenumber" name="258" href="#258">258</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="259" href="#259">259</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> getMaxCumulationBufferComponents() {
<a class="jxr_linenumber" name="260" href="#260">260</a>         <strong class="jxr_keyword">return</strong> maxCumulationBufferComponents;
<a class="jxr_linenumber" name="261" href="#261">261</a>     }
<a class="jxr_linenumber" name="262" href="#262">262</a> 
<a class="jxr_linenumber" name="263" href="#263">263</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="264" href="#264">264</a> <em class="jxr_javadoccomment">     * Sets the maximum number of components in the cumulation buffer.  If the number of</em>
<a class="jxr_linenumber" name="265" href="#265">265</a> <em class="jxr_javadoccomment">     * the components in the cumulation buffer exceeds this value, the components of the</em>
<a class="jxr_linenumber" name="266" href="#266">266</a> <em class="jxr_javadoccomment">     * cumulation buffer are consolidated into a single component, involving memory copies.</em>
<a class="jxr_linenumber" name="267" href="#267">267</a> <em class="jxr_javadoccomment">     * The default value of this property is {@link #DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS}</em>
<a class="jxr_linenumber" name="268" href="#268">268</a> <em class="jxr_javadoccomment">     * and its minimum allowed value is {@code 2}.</em>
<a class="jxr_linenumber" name="269" href="#269">269</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="270" href="#270">270</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">void</strong> setMaxCumulationBufferComponents(<strong class="jxr_keyword">int</strong> maxCumulationBufferComponents) {
<a class="jxr_linenumber" name="271" href="#271">271</a>         <strong class="jxr_keyword">if</strong> (maxCumulationBufferComponents &lt; 2) {
<a class="jxr_linenumber" name="272" href="#272">272</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalArgumentException(
<a class="jxr_linenumber" name="273" href="#273">273</a>                     <span class="jxr_string">"maxCumulationBufferComponents: "</span> + maxCumulationBufferComponents +
<a class="jxr_linenumber" name="274" href="#274">274</a>                     <span class="jxr_string">" (expected: &gt;= 2)"</span>);
<a class="jxr_linenumber" name="275" href="#275">275</a>         }
<a class="jxr_linenumber" name="276" href="#276">276</a> 
<a class="jxr_linenumber" name="277" href="#277">277</a>         <strong class="jxr_keyword">if</strong> (ctx == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="278" href="#278">278</a>             <strong class="jxr_keyword">this</strong>.maxCumulationBufferComponents = maxCumulationBufferComponents;
<a class="jxr_linenumber" name="279" href="#279">279</a>         } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="280" href="#280">280</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalStateException(
<a class="jxr_linenumber" name="281" href="#281">281</a>                     <span class="jxr_string">"decoder properties cannot be changed once the decoder is added to a pipeline."</span>);
<a class="jxr_linenumber" name="282" href="#282">282</a>         }
<a class="jxr_linenumber" name="283" href="#283">283</a>     }
<a class="jxr_linenumber" name="284" href="#284">284</a> 
<a class="jxr_linenumber" name="285" href="#285">285</a>     @Override
<a class="jxr_linenumber" name="286" href="#286">286</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> messageReceived(
<a class="jxr_linenumber" name="287" href="#287">287</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/channel/MessageEvent.html">MessageEvent</a> e) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="288" href="#288">288</a> 
<a class="jxr_linenumber" name="289" href="#289">289</a>         Object m = e.getMessage();
<a class="jxr_linenumber" name="290" href="#290">290</a>         <strong class="jxr_keyword">if</strong> (!(m instanceof ChannelBuffer)) {
<a class="jxr_linenumber" name="291" href="#291">291</a>             ctx.sendUpstream(e);
<a class="jxr_linenumber" name="292" href="#292">292</a>             <strong class="jxr_keyword">return</strong>;
<a class="jxr_linenumber" name="293" href="#293">293</a>         }
<a class="jxr_linenumber" name="294" href="#294">294</a> 
<a class="jxr_linenumber" name="295" href="#295">295</a>         <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> input = (ChannelBuffer) m;
<a class="jxr_linenumber" name="296" href="#296">296</a>         <strong class="jxr_keyword">if</strong> (!input.readable()) {
<a class="jxr_linenumber" name="297" href="#297">297</a>             <strong class="jxr_keyword">return</strong>;
<a class="jxr_linenumber" name="298" href="#298">298</a>         }
<a class="jxr_linenumber" name="299" href="#299">299</a> 
<a class="jxr_linenumber" name="300" href="#300">300</a>         <strong class="jxr_keyword">if</strong> (cumulation == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="301" href="#301">301</a>             <strong class="jxr_keyword">try</strong> {
<a class="jxr_linenumber" name="302" href="#302">302</a>                 <em class="jxr_comment">// the cumulation buffer is not created yet so just pass the input to callDecode(...) method</em>
<a class="jxr_linenumber" name="303" href="#303">303</a>                 callDecode(ctx, e.getChannel(), input, e.getRemoteAddress());
<a class="jxr_linenumber" name="304" href="#304">304</a>             } <strong class="jxr_keyword">finally</strong> {
<a class="jxr_linenumber" name="305" href="#305">305</a>                 updateCumulation(ctx, input);
<a class="jxr_linenumber" name="306" href="#306">306</a>             }
<a class="jxr_linenumber" name="307" href="#307">307</a>         } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="308" href="#308">308</a>             input = appendToCumulation(input);
<a class="jxr_linenumber" name="309" href="#309">309</a>             <strong class="jxr_keyword">try</strong> {
<a class="jxr_linenumber" name="310" href="#310">310</a>                 callDecode(ctx, e.getChannel(), input, e.getRemoteAddress());
<a class="jxr_linenumber" name="311" href="#311">311</a>             } <strong class="jxr_keyword">finally</strong> {
<a class="jxr_linenumber" name="312" href="#312">312</a>                 updateCumulation(ctx, input);
<a class="jxr_linenumber" name="313" href="#313">313</a>             }
<a class="jxr_linenumber" name="314" href="#314">314</a>         }
<a class="jxr_linenumber" name="315" href="#315">315</a>     }
<a class="jxr_linenumber" name="316" href="#316">316</a> 
<a class="jxr_linenumber" name="317" href="#317">317</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> appendToCumulation(<a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> input) {
<a class="jxr_linenumber" name="318" href="#318">318</a>         <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> cumulation = <strong class="jxr_keyword">this</strong>.cumulation;
<a class="jxr_linenumber" name="319" href="#319">319</a>         assert cumulation.readable();
<a class="jxr_linenumber" name="320" href="#320">320</a>         <strong class="jxr_keyword">if</strong> (cumulation instanceof CompositeChannelBuffer) {
<a class="jxr_linenumber" name="321" href="#321">321</a>             <em class="jxr_comment">// Make sure the resulting cumulation buffer has no more than the configured components.</em>
<a class="jxr_linenumber" name="322" href="#322">322</a>             <a href="../../../../../../org/jboss/netty/buffer/CompositeChannelBuffer.html">CompositeChannelBuffer</a> composite = (CompositeChannelBuffer) cumulation;
<a class="jxr_linenumber" name="323" href="#323">323</a>             <strong class="jxr_keyword">if</strong> (composite.numComponents() &gt;= maxCumulationBufferComponents) {
<a class="jxr_linenumber" name="324" href="#324">324</a>                 cumulation = composite.copy();
<a class="jxr_linenumber" name="325" href="#325">325</a>             }
<a class="jxr_linenumber" name="326" href="#326">326</a>         }
<a class="jxr_linenumber" name="327" href="#327">327</a> 
<a class="jxr_linenumber" name="328" href="#328">328</a>         <strong class="jxr_keyword">this</strong>.cumulation = input = ChannelBuffers.wrappedBuffer(cumulation, input);
<a class="jxr_linenumber" name="329" href="#329">329</a>         <strong class="jxr_keyword">return</strong> input;
<a class="jxr_linenumber" name="330" href="#330">330</a>     }
<a class="jxr_linenumber" name="331" href="#331">331</a> 
<a class="jxr_linenumber" name="332" href="#332">332</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> updateCumulation(<a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> input) {
<a class="jxr_linenumber" name="333" href="#333">333</a>         <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> newCumulation;
<a class="jxr_linenumber" name="334" href="#334">334</a>         <strong class="jxr_keyword">int</strong> readableBytes = input.readableBytes();
<a class="jxr_linenumber" name="335" href="#335">335</a>         <strong class="jxr_keyword">if</strong> (readableBytes &gt; 0) {
<a class="jxr_linenumber" name="336" href="#336">336</a>             <strong class="jxr_keyword">int</strong> inputCapacity = input.capacity();
<a class="jxr_linenumber" name="337" href="#337">337</a> 
<a class="jxr_linenumber" name="338" href="#338">338</a>             <em class="jxr_comment">// If input.readableBytes() == input.capacity() (i.e. input is full),</em>
<a class="jxr_linenumber" name="339" href="#339">339</a>             <em class="jxr_comment">// there's nothing to save from creating a new cumulation buffer</em>
<a class="jxr_linenumber" name="340" href="#340">340</a>             <em class="jxr_comment">// even if input.capacity() exceeds the threshold, because the new cumulation</em>
<a class="jxr_linenumber" name="341" href="#341">341</a>             <em class="jxr_comment">// buffer will have the same capacity and content with input.</em>
<a class="jxr_linenumber" name="342" href="#342">342</a>             <strong class="jxr_keyword">if</strong> (readableBytes &lt; inputCapacity &amp;&amp; inputCapacity &gt; copyThreshold) {
<a class="jxr_linenumber" name="343" href="#343">343</a>                 <em class="jxr_comment">// At least one byte was consumed by callDecode() and input.capacity()</em>
<a class="jxr_linenumber" name="344" href="#344">344</a>                 <em class="jxr_comment">// exceeded the threshold.</em>
<a class="jxr_linenumber" name="345" href="#345">345</a>                 cumulation = newCumulation = newCumulationBuffer(ctx, input.readableBytes());
<a class="jxr_linenumber" name="346" href="#346">346</a>                 cumulation.writeBytes(input);
<a class="jxr_linenumber" name="347" href="#347">347</a>             } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="348" href="#348">348</a>                 <em class="jxr_comment">// Nothing was consumed by callDecode() or input.capacity() did not</em>
<a class="jxr_linenumber" name="349" href="#349">349</a>                 <em class="jxr_comment">// exceed the threshold.</em>
<a class="jxr_linenumber" name="350" href="#350">350</a>                 <strong class="jxr_keyword">if</strong> (input.readerIndex() != 0) {
<a class="jxr_linenumber" name="351" href="#351">351</a>                     cumulation = newCumulation = input.slice();
<a class="jxr_linenumber" name="352" href="#352">352</a>                 } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="353" href="#353">353</a>                     cumulation = newCumulation = input;
<a class="jxr_linenumber" name="354" href="#354">354</a>                 }
<a class="jxr_linenumber" name="355" href="#355">355</a>             }
<a class="jxr_linenumber" name="356" href="#356">356</a>         } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="357" href="#357">357</a>             cumulation = newCumulation = <strong class="jxr_keyword">null</strong>;
<a class="jxr_linenumber" name="358" href="#358">358</a>         }
<a class="jxr_linenumber" name="359" href="#359">359</a>         <strong class="jxr_keyword">return</strong> newCumulation;
<a class="jxr_linenumber" name="360" href="#360">360</a>     }
<a class="jxr_linenumber" name="361" href="#361">361</a> 
<a class="jxr_linenumber" name="362" href="#362">362</a>     @Override
<a class="jxr_linenumber" name="363" href="#363">363</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> channelDisconnected(
<a class="jxr_linenumber" name="364" href="#364">364</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/channel/ChannelStateEvent.html">ChannelStateEvent</a> e) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="365" href="#365">365</a>         cleanup(ctx, e);
<a class="jxr_linenumber" name="366" href="#366">366</a>     }
<a class="jxr_linenumber" name="367" href="#367">367</a> 
<a class="jxr_linenumber" name="368" href="#368">368</a>     @Override
<a class="jxr_linenumber" name="369" href="#369">369</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> channelClosed(
<a class="jxr_linenumber" name="370" href="#370">370</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/channel/ChannelStateEvent.html">ChannelStateEvent</a> e) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="371" href="#371">371</a>         cleanup(ctx, e);
<a class="jxr_linenumber" name="372" href="#372">372</a>     }
<a class="jxr_linenumber" name="373" href="#373">373</a> 
<a class="jxr_linenumber" name="374" href="#374">374</a>     @Override
<a class="jxr_linenumber" name="375" href="#375">375</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> exceptionCaught(
<a class="jxr_linenumber" name="376" href="#376">376</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/channel/ExceptionEvent.html">ExceptionEvent</a> e) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="377" href="#377">377</a>         ctx.sendUpstream(e);
<a class="jxr_linenumber" name="378" href="#378">378</a>     }
<a class="jxr_linenumber" name="379" href="#379">379</a> 
<a class="jxr_linenumber" name="380" href="#380">380</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="381" href="#381">381</a> <em class="jxr_javadoccomment">     * Decodes the received packets so far into a frame.</em>
<a class="jxr_linenumber" name="382" href="#382">382</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="383" href="#383">383</a> <em class="jxr_javadoccomment">     * If an sub-class wants to extract a frame out of the buffer it should use</em>
<a class="jxr_linenumber" name="384" href="#384">384</a> <em class="jxr_javadoccomment">     * the {@link #extractFrame(ChannelBuffer, int, int)} method,</em>
<a class="jxr_linenumber" name="385" href="#385">385</a> <em class="jxr_javadoccomment">     * to make optimizations easier later.</em>
<a class="jxr_linenumber" name="386" href="#386">386</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="387" href="#387">387</a> <em class="jxr_javadoccomment">     * @param ctx      the context of this handler</em>
<a class="jxr_linenumber" name="388" href="#388">388</a> <em class="jxr_javadoccomment">     * @param channel  the current channel</em>
<a class="jxr_linenumber" name="389" href="#389">389</a> <em class="jxr_javadoccomment">     * @param buffer   the cumulative buffer of received packets so far.</em>
<a class="jxr_linenumber" name="390" href="#390">390</a> <em class="jxr_javadoccomment">     *                 Note that the buffer might be empty, which means you</em>
<a class="jxr_linenumber" name="391" href="#391">391</a> <em class="jxr_javadoccomment">     *                 should not make an assumption that the buffer contains</em>
<a class="jxr_linenumber" name="392" href="#392">392</a> <em class="jxr_javadoccomment">     *                 at least one byte in your decoder implementation.</em>
<a class="jxr_linenumber" name="393" href="#393">393</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="394" href="#394">394</a> <em class="jxr_javadoccomment">     * @return the decoded frame if a full frame was received and decoded.</em>
<a class="jxr_linenumber" name="395" href="#395">395</a> <em class="jxr_javadoccomment">     *         {@code null} if there's not enough data in the buffer to decode a frame.</em>
<a class="jxr_linenumber" name="396" href="#396">396</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="397" href="#397">397</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">abstract</strong> Object decode(
<a class="jxr_linenumber" name="398" href="#398">398</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/channel/Channel.html">Channel</a> channel, <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> buffer) <strong class="jxr_keyword">throws</strong> Exception;
<a class="jxr_linenumber" name="399" href="#399">399</a> 
<a class="jxr_linenumber" name="400" href="#400">400</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="401" href="#401">401</a> <em class="jxr_javadoccomment">     * Decodes the received data so far into a frame when the channel is</em>
<a class="jxr_linenumber" name="402" href="#402">402</a> <em class="jxr_javadoccomment">     * disconnected.</em>
<a class="jxr_linenumber" name="403" href="#403">403</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="404" href="#404">404</a> <em class="jxr_javadoccomment">     * @param ctx      the context of this handler</em>
<a class="jxr_linenumber" name="405" href="#405">405</a> <em class="jxr_javadoccomment">     * @param channel  the current channel</em>
<a class="jxr_linenumber" name="406" href="#406">406</a> <em class="jxr_javadoccomment">     * @param buffer   the cumulative buffer of received packets so far.</em>
<a class="jxr_linenumber" name="407" href="#407">407</a> <em class="jxr_javadoccomment">     *                 Note that the buffer might be empty, which means you</em>
<a class="jxr_linenumber" name="408" href="#408">408</a> <em class="jxr_javadoccomment">     *                 should not make an assumption that the buffer contains</em>
<a class="jxr_linenumber" name="409" href="#409">409</a> <em class="jxr_javadoccomment">     *                 at least one byte in your decoder implementation.</em>
<a class="jxr_linenumber" name="410" href="#410">410</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="411" href="#411">411</a> <em class="jxr_javadoccomment">     * @return the decoded frame if a full frame was received and decoded.</em>
<a class="jxr_linenumber" name="412" href="#412">412</a> <em class="jxr_javadoccomment">     *         {@code null} if there's not enough data in the buffer to decode a frame.</em>
<a class="jxr_linenumber" name="413" href="#413">413</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="414" href="#414">414</a>     <strong class="jxr_keyword">protected</strong> Object decodeLast(
<a class="jxr_linenumber" name="415" href="#415">415</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/channel/Channel.html">Channel</a> channel, <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> buffer) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="416" href="#416">416</a>         <strong class="jxr_keyword">return</strong> decode(ctx, channel, buffer);
<a class="jxr_linenumber" name="417" href="#417">417</a>     }
<a class="jxr_linenumber" name="418" href="#418">418</a> 
<a class="jxr_linenumber" name="419" href="#419">419</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">void</strong> callDecode(
<a class="jxr_linenumber" name="420" href="#420">420</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> context, <a href="../../../../../../org/jboss/netty/channel/Channel.html">Channel</a> channel,
<a class="jxr_linenumber" name="421" href="#421">421</a>             <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> cumulation, SocketAddress remoteAddress) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="422" href="#422">422</a> 
<a class="jxr_linenumber" name="423" href="#423">423</a>         <strong class="jxr_keyword">while</strong> (cumulation.readable()) {
<a class="jxr_linenumber" name="424" href="#424">424</a>             <strong class="jxr_keyword">int</strong> oldReaderIndex = cumulation.readerIndex();
<a class="jxr_linenumber" name="425" href="#425">425</a>             Object frame = decode(context, channel, cumulation);
<a class="jxr_linenumber" name="426" href="#426">426</a>             <strong class="jxr_keyword">if</strong> (frame == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="427" href="#427">427</a>                 <strong class="jxr_keyword">if</strong> (oldReaderIndex == cumulation.readerIndex()) {
<a class="jxr_linenumber" name="428" href="#428">428</a>                     <em class="jxr_comment">// Seems like more data is required.</em>
<a class="jxr_linenumber" name="429" href="#429">429</a>                     <em class="jxr_comment">// Let us wait for the next notification.</em>
<a class="jxr_linenumber" name="430" href="#430">430</a>                     <strong class="jxr_keyword">break</strong>;
<a class="jxr_linenumber" name="431" href="#431">431</a>                 } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="432" href="#432">432</a>                     <em class="jxr_comment">// Previous data has been discarded.</em>
<a class="jxr_linenumber" name="433" href="#433">433</a>                     <em class="jxr_comment">// Probably it is reading on.</em>
<a class="jxr_linenumber" name="434" href="#434">434</a>                     <strong class="jxr_keyword">continue</strong>;
<a class="jxr_linenumber" name="435" href="#435">435</a>                 }
<a class="jxr_linenumber" name="436" href="#436">436</a>             }
<a class="jxr_linenumber" name="437" href="#437">437</a>             <strong class="jxr_keyword">if</strong> (oldReaderIndex == cumulation.readerIndex()) {
<a class="jxr_linenumber" name="438" href="#438">438</a>                 <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalStateException(
<a class="jxr_linenumber" name="439" href="#439">439</a>                         <span class="jxr_string">"decode() method must read at least one byte "</span> +
<a class="jxr_linenumber" name="440" href="#440">440</a>                         <span class="jxr_string">"if it returned a frame (caused by: "</span> + getClass() + ')');
<a class="jxr_linenumber" name="441" href="#441">441</a>             }
<a class="jxr_linenumber" name="442" href="#442">442</a> 
<a class="jxr_linenumber" name="443" href="#443">443</a>             unfoldAndFireMessageReceived(context, remoteAddress, frame);
<a class="jxr_linenumber" name="444" href="#444">444</a>         }
<a class="jxr_linenumber" name="445" href="#445">445</a>     }
<a class="jxr_linenumber" name="446" href="#446">446</a> 
<a class="jxr_linenumber" name="447" href="#447">447</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">void</strong> unfoldAndFireMessageReceived(
<a class="jxr_linenumber" name="448" href="#448">448</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> context, SocketAddress remoteAddress, Object result) {
<a class="jxr_linenumber" name="449" href="#449">449</a>         <strong class="jxr_keyword">if</strong> (unfold) {
<a class="jxr_linenumber" name="450" href="#450">450</a>             <strong class="jxr_keyword">if</strong> (result instanceof Object[]) {
<a class="jxr_linenumber" name="451" href="#451">451</a>                 <strong class="jxr_keyword">for</strong> (Object r: (Object[]) result) {
<a class="jxr_linenumber" name="452" href="#452">452</a>                     Channels.fireMessageReceived(context, r, remoteAddress);
<a class="jxr_linenumber" name="453" href="#453">453</a>                 }
<a class="jxr_linenumber" name="454" href="#454">454</a>             } <strong class="jxr_keyword">else</strong> <strong class="jxr_keyword">if</strong> (result instanceof Iterable&lt;?&gt;) {
<a class="jxr_linenumber" name="455" href="#455">455</a>                 <strong class="jxr_keyword">for</strong> (Object r: (Iterable&lt;?&gt;) result) {
<a class="jxr_linenumber" name="456" href="#456">456</a>                     Channels.fireMessageReceived(context, r, remoteAddress);
<a class="jxr_linenumber" name="457" href="#457">457</a>                 }
<a class="jxr_linenumber" name="458" href="#458">458</a>             } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="459" href="#459">459</a>                 Channels.fireMessageReceived(context, result, remoteAddress);
<a class="jxr_linenumber" name="460" href="#460">460</a>             }
<a class="jxr_linenumber" name="461" href="#461">461</a>         } <strong class="jxr_keyword">else</strong> {
<a class="jxr_linenumber" name="462" href="#462">462</a>             Channels.fireMessageReceived(context, result, remoteAddress);
<a class="jxr_linenumber" name="463" href="#463">463</a>         }
<a class="jxr_linenumber" name="464" href="#464">464</a>     }
<a class="jxr_linenumber" name="465" href="#465">465</a> 
<a class="jxr_linenumber" name="466" href="#466">466</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="467" href="#467">467</a> <em class="jxr_javadoccomment">     * Gets called on {@link #channelDisconnected(ChannelHandlerContext, ChannelStateEvent)} and</em>
<a class="jxr_linenumber" name="468" href="#468">468</a> <em class="jxr_javadoccomment">     * {@link #channelClosed(ChannelHandlerContext, ChannelStateEvent)}</em>
<a class="jxr_linenumber" name="469" href="#469">469</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="470" href="#470">470</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">void</strong> cleanup(<a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <a href="../../../../../../org/jboss/netty/channel/ChannelStateEvent.html">ChannelStateEvent</a> e)
<a class="jxr_linenumber" name="471" href="#471">471</a>             <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="472" href="#472">472</a>         <strong class="jxr_keyword">try</strong> {
<a class="jxr_linenumber" name="473" href="#473">473</a>             <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> cumulation = <strong class="jxr_keyword">this</strong>.cumulation;
<a class="jxr_linenumber" name="474" href="#474">474</a>             <strong class="jxr_keyword">if</strong> (cumulation == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="475" href="#475">475</a>                 <strong class="jxr_keyword">return</strong>;
<a class="jxr_linenumber" name="476" href="#476">476</a>             }
<a class="jxr_linenumber" name="477" href="#477">477</a> 
<a class="jxr_linenumber" name="478" href="#478">478</a>             <strong class="jxr_keyword">this</strong>.cumulation = <strong class="jxr_keyword">null</strong>;
<a class="jxr_linenumber" name="479" href="#479">479</a> 
<a class="jxr_linenumber" name="480" href="#480">480</a>             <strong class="jxr_keyword">if</strong> (cumulation.readable()) {
<a class="jxr_linenumber" name="481" href="#481">481</a>                 <em class="jxr_comment">// Make sure all frames are read before notifying a closed channel.</em>
<a class="jxr_linenumber" name="482" href="#482">482</a>                 callDecode(ctx, ctx.getChannel(), cumulation, <strong class="jxr_keyword">null</strong>);
<a class="jxr_linenumber" name="483" href="#483">483</a>             }
<a class="jxr_linenumber" name="484" href="#484">484</a> 
<a class="jxr_linenumber" name="485" href="#485">485</a>             <em class="jxr_comment">// Call decodeLast() finally.  Please note that decodeLast() is</em>
<a class="jxr_linenumber" name="486" href="#486">486</a>             <em class="jxr_comment">// called even if there's nothing more to read from the buffer to</em>
<a class="jxr_linenumber" name="487" href="#487">487</a>             <em class="jxr_comment">// notify a user that the connection was closed explicitly.</em>
<a class="jxr_linenumber" name="488" href="#488">488</a>             Object partialFrame = decodeLast(ctx, ctx.getChannel(), cumulation);
<a class="jxr_linenumber" name="489" href="#489">489</a>             <strong class="jxr_keyword">if</strong> (partialFrame != <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="490" href="#490">490</a>                 unfoldAndFireMessageReceived(ctx, <strong class="jxr_keyword">null</strong>, partialFrame);
<a class="jxr_linenumber" name="491" href="#491">491</a>             }
<a class="jxr_linenumber" name="492" href="#492">492</a>         } <strong class="jxr_keyword">finally</strong> {
<a class="jxr_linenumber" name="493" href="#493">493</a>             ctx.sendUpstream(e);
<a class="jxr_linenumber" name="494" href="#494">494</a>         }
<a class="jxr_linenumber" name="495" href="#495">495</a>     }
<a class="jxr_linenumber" name="496" href="#496">496</a> 
<a class="jxr_linenumber" name="497" href="#497">497</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="498" href="#498">498</a> <em class="jxr_javadoccomment">     * Create a new {@link ChannelBuffer} which is used for the cumulation.</em>
<a class="jxr_linenumber" name="499" href="#499">499</a> <em class="jxr_javadoccomment">     * Sub-classes may override this.</em>
<a class="jxr_linenumber" name="500" href="#500">500</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="501" href="#501">501</a> <em class="jxr_javadoccomment">     * @param ctx {@link ChannelHandlerContext} for this handler</em>
<a class="jxr_linenumber" name="502" href="#502">502</a> <em class="jxr_javadoccomment">     * @return buffer the {@link ChannelBuffer} which is used for cumulation</em>
<a class="jxr_linenumber" name="503" href="#503">503</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="504" href="#504">504</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> newCumulationBuffer(
<a class="jxr_linenumber" name="505" href="#505">505</a>             <a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx, <strong class="jxr_keyword">int</strong> minimumCapacity) {
<a class="jxr_linenumber" name="506" href="#506">506</a>         <a href="../../../../../../org/jboss/netty/buffer/ChannelBufferFactory.html">ChannelBufferFactory</a> factory = ctx.getChannel().getConfig().getBufferFactory();
<a class="jxr_linenumber" name="507" href="#507">507</a>         <strong class="jxr_keyword">return</strong> factory.getBuffer(Math.max(minimumCapacity, 256));
<a class="jxr_linenumber" name="508" href="#508">508</a>     }
<a class="jxr_linenumber" name="509" href="#509">509</a> 
<a class="jxr_linenumber" name="510" href="#510">510</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="511" href="#511">511</a> <em class="jxr_javadoccomment">     * Replace this {@link FrameDecoder} in the {@link ChannelPipeline} with the given {@link ChannelHandler}. All</em>
<a class="jxr_linenumber" name="512" href="#512">512</a> <em class="jxr_javadoccomment">     * remaining bytes in the {@link ChannelBuffer} will get send to the new {@link ChannelHandler} that was used</em>
<a class="jxr_linenumber" name="513" href="#513">513</a> <em class="jxr_javadoccomment">     * as replacement</em>
<a class="jxr_linenumber" name="514" href="#514">514</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="515" href="#515">515</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="516" href="#516">516</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> replace(String handlerName, <a href="../../../../../../org/jboss/netty/channel/ChannelHandler.html">ChannelHandler</a> handler) {
<a class="jxr_linenumber" name="517" href="#517">517</a>         <strong class="jxr_keyword">if</strong> (ctx == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="518" href="#518">518</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalStateException(
<a class="jxr_linenumber" name="519" href="#519">519</a>                     <span class="jxr_string">"Replace cann only be called once the FrameDecoder is added to the ChannelPipeline"</span>);
<a class="jxr_linenumber" name="520" href="#520">520</a>         }
<a class="jxr_linenumber" name="521" href="#521">521</a>         <a href="../../../../../../org/jboss/netty/channel/ChannelPipeline.html">ChannelPipeline</a> pipeline = ctx.getPipeline();
<a class="jxr_linenumber" name="522" href="#522">522</a>         pipeline.addAfter(ctx.getName(), handlerName, handler);
<a class="jxr_linenumber" name="523" href="#523">523</a> 
<a class="jxr_linenumber" name="524" href="#524">524</a>         <strong class="jxr_keyword">try</strong> {
<a class="jxr_linenumber" name="525" href="#525">525</a>             <strong class="jxr_keyword">if</strong> (cumulation != <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="526" href="#526">526</a>                 Channels.fireMessageReceived(ctx, cumulation.readBytes(actualReadableBytes()));
<a class="jxr_linenumber" name="527" href="#527">527</a>             }
<a class="jxr_linenumber" name="528" href="#528">528</a>         } <strong class="jxr_keyword">finally</strong> {
<a class="jxr_linenumber" name="529" href="#529">529</a>             pipeline.remove(<strong class="jxr_keyword">this</strong>);
<a class="jxr_linenumber" name="530" href="#530">530</a>         }
<a class="jxr_linenumber" name="531" href="#531">531</a>     }
<a class="jxr_linenumber" name="532" href="#532">532</a> 
<a class="jxr_linenumber" name="533" href="#533">533</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="534" href="#534">534</a> <em class="jxr_javadoccomment">     * Returns the actual number of readable bytes in the internal cumulative</em>
<a class="jxr_linenumber" name="535" href="#535">535</a> <em class="jxr_javadoccomment">     * buffer of this decoder.  You usually do not need to rely on this value</em>
<a class="jxr_linenumber" name="536" href="#536">536</a> <em class="jxr_javadoccomment">     * to write a decoder.  Use it only when you muse use it at your own risk.</em>
<a class="jxr_linenumber" name="537" href="#537">537</a> <em class="jxr_javadoccomment">     * This method is a shortcut to {@link #internalBuffer() internalBuffer().readableBytes()}.</em>
<a class="jxr_linenumber" name="538" href="#538">538</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="539" href="#539">539</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">int</strong> actualReadableBytes() {
<a class="jxr_linenumber" name="540" href="#540">540</a>         <strong class="jxr_keyword">return</strong> internalBuffer().readableBytes();
<a class="jxr_linenumber" name="541" href="#541">541</a>     }
<a class="jxr_linenumber" name="542" href="#542">542</a> 
<a class="jxr_linenumber" name="543" href="#543">543</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="544" href="#544">544</a> <em class="jxr_javadoccomment">     * Returns the internal cumulative buffer of this decoder.  You usually</em>
<a class="jxr_linenumber" name="545" href="#545">545</a> <em class="jxr_javadoccomment">     * do not need to access the internal buffer directly to write a decoder.</em>
<a class="jxr_linenumber" name="546" href="#546">546</a> <em class="jxr_javadoccomment">     * Use it only when you must use it at your own risk.</em>
<a class="jxr_linenumber" name="547" href="#547">547</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="548" href="#548">548</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> internalBuffer() {
<a class="jxr_linenumber" name="549" href="#549">549</a>         <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> buf = cumulation;
<a class="jxr_linenumber" name="550" href="#550">550</a>         <strong class="jxr_keyword">if</strong> (buf == <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="551" href="#551">551</a>             <strong class="jxr_keyword">return</strong> ChannelBuffers.EMPTY_BUFFER;
<a class="jxr_linenumber" name="552" href="#552">552</a>         }
<a class="jxr_linenumber" name="553" href="#553">553</a>         <strong class="jxr_keyword">return</strong> buf;
<a class="jxr_linenumber" name="554" href="#554">554</a>     }
<a class="jxr_linenumber" name="555" href="#555">555</a> 
<a class="jxr_linenumber" name="556" href="#556">556</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="557" href="#557">557</a> <em class="jxr_javadoccomment">     * Extract a Frame of the specified buffer. By default this implementation</em>
<a class="jxr_linenumber" name="558" href="#558">558</a> <em class="jxr_javadoccomment">     * will return a extract the sub-region of the buffer and create a new one.</em>
<a class="jxr_linenumber" name="559" href="#559">559</a> <em class="jxr_javadoccomment">     * If an sub-class want to extract a frame from the buffer it should use this method</em>
<a class="jxr_linenumber" name="560" href="#560">560</a> <em class="jxr_javadoccomment">     * by default.</em>
<a class="jxr_linenumber" name="561" href="#561">561</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="562" href="#562">562</a> <em class="jxr_javadoccomment">     * &lt;strong&gt;Be sure that this method MUST not modify the readerIndex of the given buffer&lt;/strong&gt;</em>
<a class="jxr_linenumber" name="563" href="#563">563</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="564" href="#564">564</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="565" href="#565">565</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> extractFrame(<a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> buffer, <strong class="jxr_keyword">int</strong> index, <strong class="jxr_keyword">int</strong> length) {
<a class="jxr_linenumber" name="566" href="#566">566</a>         <a href="../../../../../../org/jboss/netty/buffer/ChannelBuffer.html">ChannelBuffer</a> frame = buffer.factory().getBuffer(length);
<a class="jxr_linenumber" name="567" href="#567">567</a>         frame.writeBytes(buffer, index, length);
<a class="jxr_linenumber" name="568" href="#568">568</a>         <strong class="jxr_keyword">return</strong> frame;
<a class="jxr_linenumber" name="569" href="#569">569</a>     }
<a class="jxr_linenumber" name="570" href="#570">570</a> 
<a class="jxr_linenumber" name="571" href="#571">571</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> beforeAdd(<a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="572" href="#572">572</a>         <strong class="jxr_keyword">this</strong>.ctx = ctx;
<a class="jxr_linenumber" name="573" href="#573">573</a>     }
<a class="jxr_linenumber" name="574" href="#574">574</a> 
<a class="jxr_linenumber" name="575" href="#575">575</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> afterAdd(<a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="576" href="#576">576</a>         <em class="jxr_comment">// Nothing to do..</em>
<a class="jxr_linenumber" name="577" href="#577">577</a>     }
<a class="jxr_linenumber" name="578" href="#578">578</a> 
<a class="jxr_linenumber" name="579" href="#579">579</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> beforeRemove(<a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="580" href="#580">580</a>         <em class="jxr_comment">// Nothing to do..</em>
<a class="jxr_linenumber" name="581" href="#581">581</a>     }
<a class="jxr_linenumber" name="582" href="#582">582</a> 
<a class="jxr_linenumber" name="583" href="#583">583</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> afterRemove(<a href="../../../../../../org/jboss/netty/channel/ChannelHandlerContext.html">ChannelHandlerContext</a> ctx) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="584" href="#584">584</a>         <em class="jxr_comment">// Nothing to do..</em>
<a class="jxr_linenumber" name="585" href="#585">585</a>     }
<a class="jxr_linenumber" name="586" href="#586">586</a> 
<a class="jxr_linenumber" name="587" href="#587">587</a> }
</pre>
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